Vehicular parking brakes use a cable system to manually engage and release the brakes. The park brake system may include a handle or lever that is coupled to a first end of a first cable. A second end of the first cable is coupled to an adjuster. More specifically, the second end of the first cable extends through an aperture in the adjuster, with an adjusting nut attached to the second end of the first cable to secure the first cable to the adjuster. A left rear cable extends from the adjuster to a left rear brake, and a right rear cable extends from the adjuster to a right rear brake. Tightening the adjusting nut against the adjuster shortens the effective length of the first cable, thereby increasing the tension in the park cables. In contrast, loosening the adjusting nut relative to the adjuster lengthens the effective length of the first cable, thereby decreasing the tension in the park cables.
When the park brake system is actuated, i.e., disposed in an applied position, then the park cables are tensioned to a level sufficient to engage the brakes of the vehicle. When the park brake system is disengaged, slack is introduced into the park cables to reduce the tension in the park cables. Accordingly, when the park brake system is disengaged, the park brake system may be referred to as being in a slack position, and the amount of tension in the cables when disposed in the slack position may be referred to as a target tension level.
The park cables must be properly tensioned to function properly. The lever or handle moves the park cables a pre-defined distance when moving from the slack position to the applied position in order to obtain the requisite tension level in the park cables. If the park cables include excess slack, i.e., if the park cables are too long, then the park brake system will fail to achieve the requisite tension level and will not apply enough force to the brakes to properly engage the brakes. In contrast, if the park cables do not include enough slack, i.e., if the park cables are too short, then the park cables will be excessively tensioned, and will create brake drag, i.e., a continuously applied braking force. Accordingly, the tension of the park cables, i.e., the length of the park cables when in the slack position, must be properly set to the target tension level in order for the park brake system to function properly.